Cream butter, 1/2 cup sugar, vanilla and salt until fluffy. Stir in flour until well blended.,______,Shape in 1-inch balls.,Place 1-inch apart on ungreased cookie sheet and bake in preheated 375° oven until light golden, 12 to 15 minutes.,Remove to rack (close to each other) and while cookies are still warm, sift heavily with confectioners sugar.,Cool, then store airtight in cool, dry place.,Before serving, sift cookies with more confectioners sugar.,Makes about 48.